Drafting board



Nov. 22, 1949 Filed June 25, 1946 V R. D. SMITH DRAFTING sown 2 Sheets-Sheet 1 QQQQQ G Immml INVEN TOR.

ATT RNEY.

Nov. 22, 1949 R.` D. SMITH 2,489,165

DRAFTING BOARD Patented Nov. 22, 1949 UNITED STATES PATENT UFFICE DRAFTING 4BOARD Raymond D. Smith,.Madson, Wis.

`Application.Julie 25, 1946,'Seria1 No. `679,133

1 Claim. 1

My invention refers to a drafting kit and it has for its primary object to provide a simple, inexpensive drafting apparatus, comprising a rectangular board having a pair of right angled raised track-strips upon twoconverging straight edges -of `the board, the same beingstopped oi at `the associatedboard corner to form a throat.

The board is `associated with an L-shaped iat right angle unit, having arms terminating with different end angles, and various scales upon the edges thereof, together with a series of apertures forming open geometrical figures for tracing.

With these two units and proper manipulation of the hat armed angle, `all .machine working drawings, or other illustrations, may be made with minimum lost motions. Hence, the twopiece drafting unit will eliminate the necessity for an elaborate set of drawing instruments and also much valuable Vtime in shifting from one instrument to the other.

A further object of my invention is to provide the track-strips with spring controlled clampsfor attaching drawing paper of a variety of sizes to the board, whereby the margins of the drawing paper are not mutilated by tacks, glue strips, or the like.

With the above and other objects in view, which will appear as the description proceeds, the invention` resides in the novel construction, combination and arrangement of parts, substantially as hereinafter described, and more particularly dened by the appended claim, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claim.

In the accompanying drawings is illustrated one complete example of the physical embodiment of the `present invention constructed according to the best modeso `far devisedfor the practical application of the .principles thereof.

In the drawings:

Fig. l represents a plan view of a drawing apparatus embodying the features of my invention.

Fig. 1a is an edge view of the same.

Fig. 2 is a face view of the apparatus upon a reduced scale illustrating in dotted lines various positions that may be assumed by the L-shaped angle.

e Fig. 3 is a plan view of a group of different sized sheets of paper which may be afxed to the board.

Fig. 4 is a diagrammatic face view of a circle which may be formed by one of the templet apertures.

Fig. 5 is a similar view of a hexagon.

Fig. 6 isa similar diagrammatic view illustrating a quarter circleznerged into right angle lines, .whichmay be described through a templet aperture in conjunction with lines ruled by the angle.

Fig. '7 is an enlarged sectional elevation through the drawing board track-strip and spring clamping mechanism, the section being indicated by line 'I---ll of Fig. 11. 1 Fig. 8 is a detailed side elevation of the `board' track-strip and spring clamping mechanism.

Fig. 9 is a fragmentary end elevation of the board track-strip and spring for gripping the paper.

Fig. l0 is a plan v-iew of said paper gripping spring. particularly.illustrating a locking slot associated with aknurled-head; and

Fig. 11 is a plan view of the spring clamping mechanism and track-strip.

Referring .by characters to the drawings, B indicates a rectangular drawing board formed by a series of ber laminations. Riveted or otherwise secured thereto is a pair of the converging and raised track-strips G, the same being stopped off a predetermined distance from the associated corner of the board to form a clear angle throat B'.

As best illustrated in Fig. 8 of the drawings,

the inner portion of the track-strip is cut away to form a paper receiving recess, which recess, as indicated in dotted lines in Fig. 1 of the draw--l ings, extends from` end to end of either trackstrip G.

As shown in Fig. 1 `of the drawings, the board has fitted thereto a `s'heet of drawing paper A,

L the .converging edges of which are tucked under the recess of the track-strips. These edges of the paper are iirmly clan'iped tothe drawing board by U-shaped leaf springs seated under the trackstrip, .the :said springs terminating at their inner free ends with downwardly extended teeth C, which teeth pass. through apertures in the trackstrips, as best illustrated `in Figs. '7 and 8 of the drawings. It is understood, in this exemplication of my invention, one clamping spring for each track-strip is utilized.

As indicated in Figs. 7, 8 and 10` of the drawings, the upper face of each spring is provided with a keyhole slot D for interlocking engagement with a rib J extending downwardly from the hub of a knurled locking button N.

The locking button N is loosely mounted upon a stud N' which extends upwardly from the board and through the track-strip, spring slot, and head, the same being held in position upon the stud by an end cap upon said stud N.

As best shown in Fig. 11 of the drawings, the upper face of the rotary button N is formed with a line Q extending therethrough, which line indicates the position of the rib J. The rib, as shown in Figs. 8 and 11, is crosswise of the spring. Hence, the spring tooth C, as shown in Figs. 8 and 11, is in a depressed position to secure the paper firmly.

As shown in Fig. 7 of the drawings, the rib J, of the head, is in alignment with the spring and keyhole slot D therein, whereby the tooth C of the spring is freed from the board.

While I have illustrated and described the board as built up from laminations, it is obvious that said board and track-strips may, in some instances, be fabricated from any suitable material such as plastic, or the like, in which case the track-strips G may form an integral part of the board, Without departing from the spirit of my invention.

As illustrated, the board may also be provided with rubber pads P for holding the same against slippage and also for the purpose of protecting the face of a desk when the board is shifted thereabout. As shown in Fig. 1 of the drawings, I provide an L-shaped dat angle R formed with right angle arms, the same being constructed from any suitable transparent material. The outer straight edges of each angle arm is provided with graduated scales and also a graduated scale upon the inner straight edge of one of said arms, is provided. These scales are in fractional inches, tenths of inches, and one of the scales in millimeters, as indicated at K, the other scales being indicated by the reference characters S and E, respectively.

To facilitate scale drawings, the end R of one angle armis cut away upon a 45 angle and at this point the said arm is also provided with a quarter degree scale. The opposite arm end R is cut away at an angle of 30 or 60, these angles being, in common drafting practice, the most popular. i

As noted, the inner edge of one of the angled arms is formed with a plurality of irregular curves I to meet various drawing designs. The face portion of each arm is formed with a series of apertures T of different areas outlining certain geometrical figures, and each gure has extending from its edge quarter markings M, and as indicated by the lines Y-Y and X--X of Figs. 4 and 5. These markings are for the purpose of ascertaining the center of the gures to be drawn.

Such geometrical figures include, for example, circles of various sizes, ellipses, hexagons, squares, triangles and diamonds. It is obvious that these gures may be varied indefinitely.

In practice, when it is desired to form a hexagonal figure, after a certain desired center is indicated upon the drawing paper, the hexagonal aperture of the angle arm is tted over this center 4 and a hexagon is produced with a pencil by moving the same around the edges of the aperture. The same method is employed in reproducing all figures.

It should be noted that all of the markings, such as squares or the like upon the angle arms, are upon the lower faces of the angle, whereby accurate measurements may be taken without misleading shadows.

It should be further noted that the edges of the right angle unit are perpendicular and thick enough to use a ruling ink pen. In practice the abrupt edge is essential when using an inking pen for ruling lines.

It is apparent, in the operation of the apparatus, that the angle R may be slid along each track, as indicated in Fig. 2 of the drawings, and also the arms of the angle may be shifted through the throat B', whereby the full scope of the working faces of the angle are obtained.

I claim:

A rectangular drafting board, comprising a pair of track-strips secured to the converging edges of the board and terminating at a distance from the intersecting corner of said board, to form a clearance throat for the legs of a triangle, each track-strip being provided with a longitudinal paper receiving recess at its inner face and an aperture communicating with the paper receiving recess, a U-shaped leaf spring having a retaining leg seated under the track-strip and an upper spring leg extending over said track-strip, the same terminating with a downwardly extended paper biting tooth seated in the strip aperf ture, the said upper spring leg having a keyhole slot therein, a headed stud carried by the drafting board extending upwardly through the leaf spring retaining leg and keyhole slot of the upper leg, and a locking button rotatably mounted upon the headed stud having a rib engageable with the keyhole slot, whereby a sheet of paper is released or clamped to the drafting board.

RAYMOND D. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,745,188 Pipirs Jan. 28, 1930 1,987,382 Von Zimmermann Jan. 8, 1935 2,000,247 Niukkanen et al May 7, 1935 2,060,355 Twomley Nov. 10, 1936 2,393,228 Blitz Jan. 22, 1946 D. 137,459 Colmery Mar. 14, 1944 FOREIGN PATENTS Number Y Country Date 465,178 France Jan. 31, 1914 814,649 France Mar. 22, 1937 818,327 France June 14, 1937 

